Electromagnetic drill unit



Aug. 28, 1956 E. w. BUCK ELECTROMAGNETIC DRILL UNIT 3 Sheets-Sheet 1Original Filed May 10, 1952 INVENTOR EUGENE W BUCK WM YMM/ ATTORNEY;

Aug. 28, 1956 E. w. BUCK Re. 24,203

ELECTROMAGNETIC DRILL UNIT 3 Sheets-Sheet 2 Original Filed May 10, 1952INVENTOR EUGENE W BUCK ATTORNEYS Aug. 28, 1956 E. w. BUCKELECTROMAGNETIC DRILL UNIT '5 Sheets-Sheet 3 Original Filed May 10, 1952INVENTOR .EUGENE W BUCK fiTTO RN EVS United States PatentELECTROMAGNETIC DRILL UNIT Eugene W. Buck, Campbell, Calif.

Original No. 2,672,770, dated March 23, 1954, Serial No. 287,233, May10, 1952. Application for reissue June 6, 1955, Serial No. 513,622

8 Claims.. (Cl. 77-7) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

The present invention is directed to a portable, electromagneticallysupported drill unit, and in particular represents modifications of thestructure shown in my copending application, Serial No. 254,993, filedNovember 6, 1951, on Portable Magnetic Base Drill [.1 now Patent2,622,457, dated December 23, 1952.

The principal object of the present invention is to provide anelectro-magnetic drill unit which is of simplified but sturdy anddependable construction, and of compact assembly; the unit including atubular main post which houses the rectifier, thus effectively shieldingthe same against damage during normal use of said unit.

Another important object of the instant invention is to provide anelectro-magnetic drill unit which is rigidly magnetically secured to ametal work-piece and thus very stable when in use; the inventioncontemplating the employment of one or more electro-magnetic feetdisposed in symmetrical arrangement relative both to the drill and to arear stabilizing leg which the device includes.

A further object of this invention is to provide an electro-magneticdrill unit which permits of its magnetic attachment to a flat metalwork-piece in a position for convenient drilling close to an edge of theworkpiece or in a corner thereof.

An additional object of the invention is to provide, as an attachment, adevice which permits the drill unit to be easily converted for use, inclamping engagement, on a round shaft or pipe.

It is also an object of the invention to provide an electro-magneticdrill unit which is designed for ease and economy of manufacture; theunit being especially adapted, but not limited, for use with aninitially separate portable or hand-type electric drill.

Still another object of the invention is to provide a practical andreliable electro-magnetic drill unit, and one which will be exceedinglyeffective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relativearrangement of parts as will full appear by a perusal of the followingspecification and claims.

In the drawings:

Figure 1 is a side elevation of the electro-m-agnetic drill unit as inuse with a single electro-magnetic foot; the view being broken away inpart to show certain details. I

Figure 2 is a sectional plan view taken through the main post directlyabove the base plate; the view showing such plate as arranged with dualelectro-magnetic feet.

Figure 3 is a fragmentary side elevation of the same.

Figure 4 is a fragmentary elevation showing the lower portion of thedevice as modified to provide a swivel connection between the lower endof the main post with an electro-magnetic foot.

Figure 5 is a side elevation showing the attachment device which permitsthe drill unit to be used on a round shaft or pipe.

Re. 24,203 Reissued Aug. 28, 1956 Figure 6 is an end elevation of saiddevice as clamped on a shaft; the device being shown detached from theremainder of the drill unit.

Figure 7 is a cross section on line 77 of Figure 1.

Figure 8 is a diagram of the circuit.

Referring now more particularly to the characters of reference on thedrawings, and at present to Figures 1, 7 and 8, the electro-magneticdrill unit comprises an upstanding, tubular post or housing 1 fitted, atits lower end, with an enlarged circular base plate 2 which is dis--posed substantially horizontally.

Such base plate 2 is secured in matching relation on top of anelectro-magnetic foot, indicated generally at 3.

The electro-magnetic foot 3 comprises a circular body 4 of iron; whichbody is formed internally with an annular channel 5 which houses aring-like electro-magnetic coil 6. The coil 6 is maintained in thechannel 5 by means of a bottom ring 7 whose displacement is normallyprevented by set screws 8. The base plate 2 is afiixed to the top of thebody 4 by cap screws 9.

A bracket 10 is fixed to, and projects rearwardly from, the upstandingtubular post 1 at the back of the latter; such bracket 10 being ofrelatively short extent radially of said post.

At its outer end the bracket 10 is formed with a vertical-axis boss 11,and the upper end of a rear stabilizing.

leg 12 is adjustably threaded through such boss from below. The rear leg12 is adjusted in its downward projection to bear on the metallicwork-piece 13 in a manner so that the electro-magnetic foot 3 may restflush on said work-piece.

A locking nut 14, threaded on the upper end of the leg 12, normallybears against the boss 11 to prevent such leg from turning out ofadjustment.

At the upper front portion thereof the post 1 is fixed in connectionwith a vertical guideway 15, which guideway extends from a pointintermediate the ends of the post 1 upwardly to a top termination somedistance thereabove.

The guideway 15 includes side grooves 16 facing each other, and a slide17 runs vertically in the guideway 15, being carried at opposite edgesin the groves 16. Friction strips 18 are disposed in the grooves 16 andprevent too free motion of said slide 17; one of said friction strips 18being subject to adjustment by one or more adjustment screws 19.

The slide 17 is adapted to be manually run upwardly or downwardly asfollows:

Such slide 17 is fitted, on the inner face thereof and centrally of itsside edges, with a vertical rack 20, and a pinion 21 disposed in apinion housing 22 runs in mesh with said rack. The pinion housing 22 isdisposed above the upper end of the post 1, and the pinion 21 is carriedon a cross shaft 23 which extends horizontally from side to side of saidhousing. Additionally, the housing 22 encloses a coil-type return spring24 connected with said cross shaft 23.

At one end the cross shaft 23 projects out of the housing 22, and isthere fitted with a spider-type handle 25.

On the front side thereof, and adjacent the top, the slide 17 carries anattachment plate 26 secured to said slide by screws 27; there being anattachment arm 28 which projects forwardly from the plate 26 formatching engagement with the handle 29 of a vertically disposed,normally separate portable electric drill 30. The arm 28 is attached tothe handle 29 by a U-clamp 31.

Additional connection is provided between the drill 30 and the slide 17by means of a screw plug 32 threaded into the drill body, and attachedto the slide by a screw 33 adjacent the lower end of said slide. a

As so detachably mounted, the drill 30 projects directly downwardly,with the drill chuck 34 above the workpiece 13, but sufliciently closefor a twist drill 35 carried by said chuck to run downward into suchworkpiece. The base structure comprising the pole member 4 and thestabilizing leg 1 2, spaced from each other, provides an extendedstabilizing or supporting line for the drill.

The coil 6 of the electromagnetic foot 3 is adapted to be D. Cenergized, and to this end a cylindrical torque free rectifier 36 offull-wave bridge type comprising only stationary parts is disposed inthe post 1 in protective relation, being secured therein by suitablemeans such as a set screw 37. A known full-wave bridge type rectifier ofthe kind referred to is disclosed in the patent to Bonner 2,459,788,granted January 25, 1949.

The circuit, which includes the coil 6 and rectifier 36 (see Figure 8 inconjunction with Figure 1), comprises a main A. C. supply circuit 38 inthe form of a cord which leads into the post 1 to connection with therectifier 36; there being a switch 39 in one lead of said circuit, 'andwhich switch is mounted on the side of the post 1 adjacent the lower endthereof.

The rectifier output circuit 40, in the form of a cord, leads out of thepost 1 and thence passes downwardly through the base plate toconnection, internally, with the coil 6 of the foot 3. In order topermit of detachment of the foot '3, the cord 40 has a plug and socketunit 41 interposed therein, and said cord 40 passes through an openendedslot 42 in the base plate 2.

A signal light 43 is Wired across the main circuit 38 beyond the switch39, serving to indicate to the operator when the unit is electricallyenergized; said signal light being mounted on the front of the post 1.

An electric socket 44 for plug-in of the cord (not shown) whichenergizes the drill 30 is mounted on one side of the bracket in parallelconnection with the main circuit 38.

With the above described electro-ma'gn'etic drill unit, the electricdrill is carried on a rigid, stable stand when the electromagnetic foot3 is adhered to the workpiece 13 with the rear leg 12 likewise bearingon the same. Thereafter, by the simple expedient of working the handle.25, the operator can run the drill directly into the work. Also, byreason of the relative arrangement of the parts=- i-. e. the twist drill35 ahead of the foot 3, and the leg 12 rearwardly of the latter -thedevice can be set so that the drill 35 may work near an edge or into acorner of said workpiece.

For heavy-duty work, or increased stability, it may be desirable toemploy a pair of electromagnetic feet, and to this end the base plate 2is formed, on opposite sides but adjacent the front, with laterallyoutwardly projecting attachment lugs 45 which are forked. These lugsappear on the base plate 2, as shown in Figure 1, and in Figures 2 and 3such lugs are'shown in use.

To employ two electromagnetic feet, indicated at 4'6 and 47, the foot 3is detached, and in lieu thereof the feet 46 and 47 are connected to thelugs 45 in adjacent but spacedside by side relation. The feet 46 and 47include upstanding tongues 48 and 49 which are bolted into thecorresponding lugs 45, as shown; such feet being of the sameconstruction and electrical arrangement with respect to the coil as thefoot 3. The feet 46 and 47 have electric supply 'co'r'ds 50 and 51 whichlead upwardly; the cord -51 being adapted to connect with the plug andsocket'uni't 41 on the post 1, while the cord 50 has similar connection(not shown) on the opposite side of said post.

In the embodiment of Figure 4 the post is indicated at 52, and at itslower end has pivotal connection, as at 53, with the base plate 54secured to the electromagnetic foot 55, as aforesaid. The purpose of thepivotal connection 53, which has a transverse horizontal 'axis, is topermit the foot to accommodate itself to any unevenness which may existinthe workpiece 56.

In order to prevent the .post 52 from tipping too far forwardly aboutthe pivotal "axis 53 when the 'foot 55 is deenergized, a stop screw 59is threaded through a forwardly projecting boss 60 and extendsdownwardly to adjacent but short of the foot 55 ahead of said pivotalaxis.

Under certain working conditions it may be desired to employ the devicein connection with radial drilling of a round workpiece, such as a pipeor a shaft. To accomplish this I provide the attachment device shown inFigures 5 and 6.

This device comprises a saddle block 61 adapted to seat on the roundworkpiece 62, the saddle block 61 being attached to the lower end of thepost P of the device by securing said block to the base plate, hereindicated at 63. In the present instance the base plate 63 is shown ashaving pivotal connection 64 with the post in the manner of Figure 4,but a fixed connection, as in Figure 1, can be employed if desired. Achain 65 is anchored to one end of the saddle block 61, as at 66, andthence extends downwardly under the workpiece 62 and upwardly over asprocket 67 fixed on a cross shaft 68 journaled in connection with, butspaced outwardly from the saddle block 61-.

After manual engagement of the chain 65 under the workpiece and over thesprocket 67, said chain is tightcued by rotation of the cross shaft 68through the medium of a hand lever 69 thereon.

Intermediate the sprocket 67 and hand lever 69, the cross shaft 68carries a ratchet wheel 70 with which a releasable holding pawl 71cooperates. The holding pawl 71, working against the ratchet wheel 70,maintains the chain 65 taut about the workpiece 62.

With the above described attachment device the drill unit can beeflectively set to drill radially into the workpiece '62.

From the foregoing description it will be readily seen that there hasbeen produced such a device as will substantially fulfill the objects ofthe invention, as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims,

Having thus described the invention the following is claimed as new anduseful, and upon which Letters Patent are desired:

1. A drill unit comprising an upstanding post, a support for an electricdrill, means mounting the support on the post at the front for up anddown motion, a pair of electromagnetic feet disposed in transverselyspaced relation symmetrically below the post, means securing the feet inconnection with the lower end of the post, a rigid bracket projectingfrom the lower portion of the post at the rear, and a stabilizing legextending downward from the outer end of the bracket.

2. A drill unit comprising an upstanding post, a support for an electricdrill, means mounting the support on the post at the front for up anddown motion, an electromagnetic :foot disposed below the post, a baseplate between the lower end of the post and the foot and secured to thelatter, a rigid bracket projecting from the lower portion of the post atthe rear, a vertically adjustable stabiliiing leg extending downwardfrom the outer end of the bracket, and a pivot connecting the base plateand the lower end of the post; the axis of the pivot being disposed atright angles to a median line drawn between a drill and the leg.

3. A drill unit comprising an upstanding post, a support for an electricdrill, means mounting the support on the post for up and down movementand so that the axis of a drill is spaced fromthe front side of the posta predetermined distance, an electromagnetic foot mounted in connectionwith the post directly below the same, a bracket projecting tearwardlyfrom the post adjacent the lower end thereof, and a stabilizing legdepending from the bracket; the lower end of the leg, post and drilllying substantially in a common horizontal line.

4. A drill unit comprising an upstanding post, a support for an electricdrill, means mounting the support on the post for up and down movementand so that the axis of a drill is spaced from the front side of thepost a predetermined distance, an enlarged base plate on the lower endof the post for removable mounting on a magnetic foot, lugs projectinglaterally from the base plate and post on opposite sides of the latter,and elements removably connected to :and depending from the lugs formounting connection with transversely spaced magnetic feet when thefirst named foot is dismounted from the base plate.

5. A portable unitary electromagnetic support unit for a normallyseparate portable electric drill, said unit comprising an upstandingtubular post having a vertically disposed guideway thereon, a supportfor the electric drill, means for detachably mounting the electric drillon said support, means mounting said support in said guideway for up anddown movement with the axis of the drill in an upright direction, meansincluding a centrally disposed element on said support for efiecting upand down movement thereof, a base structure connected to and supportingsaid tubular post and extending transversely thereto and including meansforming an extended stabilizing line for the drill, said base structureincluding an electromagnetic pole member having a recess therein andalso including an electromagnetic coil in said recess, said pole memberproviding a supporting foot structure under said post, and electricalmeans for energizing said electromagnetic coil including a torque freerectifier comprising only stationary parts in said tubular post.

6. A portable unitary electromagnetic support unit for a normallyseparate portable electric drill, said unit comprising an upstandinghollow main frame, a sup ort for the electric drill, means fordetachably mounting the electric drill on said support, means mountingthe support on said frame for up and down movement with the axis of thedrill in an upright direction, a base structure connected to andsupporting said main frame and extending transversely thereto to providean extended stabilizing line for the drill, said base structureincluding an electromagnetic pole member having a recess therein andalso including an electromagnetic coil in said recess, said pole memberproviding a supporting foot structure under said frame, and electricalmeans for energizing said electromagnetic coil including a torque freerectifier comprising only stationary parts in said hollow main frame.

7. A portable unitary electromagnetic support unit for a normallyseparate portable electric drill constructed for operation by an A. C.current, said unit comprising an upstanding hollow main frame, a supportslide for the electric drill, means for detachably mounting the electricdrill on said support slide, means mounting the support slide on saidframe for up and down sliding movement with the axis of the drill in anupright direction, a base structure connected to and supporting saidmainframe and extending transversely thereto to provide an extendedstabilizing line for the drill, said base structure including anelectromagnetic pole member having a recess therein and also includingan electromagnetic coil in said recess, said pole member providing asupporting foot structure under said frame, and electrical means foreneregizi'ng said electromagnetic coil including a torque free rectifiercomprising only stationary parts in said hollow main frame, a singleelectrical cord electrically connected to said rectifier and extendingfrom said unit for connection to a source of A. C, current, and anelectrical outlet for said drill on said unit and connected to said cordto receive A. C. current therefrom.

8. A portable unitary electromagnetic support unit for a normallyseparate portable electric drill constructed for operation by an A. C.current, said unit comprising an upstanding hollow main frame, a supportslide for the electric drill, means for detachably mounting the electricdrill on said support slide, means mounting the support slide on saidframe for up and down sliding movement with the axis of the drill in anupright direction, a base structure connected to and supporting saidmain frame and extending transversely thereto to provide an extendedstabilizing line for the drill, said base structure including anelectromagnetic pole member having a recess therein and also includingan electromagnetic coil in said recess, said pole member providing asupporting foot structure under said frame, and electrical means forenergizing said electromagnetic coil including a torque free rectifiercomprising only stationary parts in said hollow main frame, a singleelectrical cord electrically connected to said rectifier and extendingfrom said unit for connection to a source of A. C. current, onelectrical outlet for said drill on said unit and connected to said cordto receive A. C. current therefrom, and a switch between said rectifierand mid cord.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 596,375 Murchie Dec. 28, 1897 676,043 Lincoln June11, 1901 1,023,921 Brown Apr. 23, 1912 1,176,584 Madge'tt Mar. 21, 19161,184,829 Crist May 30, 1916 2,024,390 Roesch Dec. 17, 1935 FOREIGNPATENTS 369,374 France Ian. 10, 1907 583,158 Great Britain Dec. 10, 1946691,267 France July 7, 1930 896,945 France May 8, 1944

